1. Field of the Invention
The present invention relates to agitating elements for vertical axis clothes washing machine, and particularly to such agitator elements as have variable oscillation speeds or strokes.
2. The Prior Art
Ruble U.S. Pat. No. 3,987,652, assigned to the same assignee as the present invention, discloses an agitator including an oscillating body portion with rigid vanes and an auger portion which rotates unidirectionally in response to the oscillation of the body portion. A one-way clutch such as a ratchet clutch positively drives the auger in one direction, while the resistance of a tightly packed clothes load about the auger vanes may resist movement of the auger in the nondriving direction. When the clothes load is insufficient to prevent reverse oscillation, the auger will tend to oscillate with the lower scrubbing vanes and the skirt.
U.S. Pat. No. 3,213,651 discloses a washing machine having an agitator whose oscillatory stroke length may be selectively varied between 0.degree. and 160.degree. by means of lost motion devices carried in the top of the barrel. A first embodiment uses a nut riding on threads on the oscillating drive shaft and engaging an inner surface of the agitator. The position of an agitator cap controls the vertical space available to the nut for non-driving movement. In a second embodiment, shown in FIGS. 4-7, selected discrete stroke lengths can be obtained by rotating the agitator cap to vary the axial position of a member 73. Such axial position determines which of three variable-width slots 78, 79, 80 is engaged, for corotation of the drive shaft and agitator.
U.S. Pat. No. 2,273,566 shows a washing machine agitator having a stroke variable between zero and full travel, the stroke being varied by adjustment of a cap on the agitator to change frictional forces between the agitator barrel and the drive shaft.
Further, U.S. Pat. Nos. 2,821,840 and 2,422,545 disclose hydraulic drives and controls for varying agitator stroke length and stroke speed.